1. Field of the Invention
This invention relates to an adjustable cable end fitting which has automotive and non-automotive cable applications. More specifically, the adjustable cable end fitting is attached to the outer sheath of a control cable and allows adjustable placement of the end of the cable sheath relative to the cable.
2. Discussion of the Related Art
Force transmitting cables are used to transmit mechanical forces between various devices. One application of these control cables is used in an automotive heater-air conditioner application. The cables are used to transmit mechanical forces between the control lever on the instrument panel and the temperature/mode function doors in the air distribution plenum. In most cases, the forces are transmitted along a curved path between these components. Typically the cable or conduit is secured to an apertured end fitting having a flange or other mechanism thereon which is adapted to be attached to a support structure and the cable movably disposed within the conduit and the end fitting.
The conduit or sheath is suitably secured at opposite ends to the support structure of the vehicle and is arranged so that the end of the cable may be attached to the element to be controlled while the opposite end of the cable is attached to a cntrolling member such as a knob or a lever located on the instrument panel. While the normal force transmitting member is a cable, other force transmitting members are possible and are contemplated by this invention.
In several known systems, the end fitting was normally provided with a mounting aperture in a flange portion thereof so as to permit mounting by means of a screw or other means to a suitable support member of the vehicle. In this type of system, a screw was necessary to attach the end fitting to the support member and thus an additional tool was required for installation of the end fitting. These systems did not allow for easy, tool free adjustment of the cable sheath relative to the cable member. Depending on the assembly fixtures, devices or procedures used it was possible for these cable systems to be improperly positioned relative to the lever or knob which the user push, pulled or rotated to select the desired mode or temperature of heating or air conditioning.
Systems were developed to rigidly position the doors and levers with respect to each other with the intent of ensuring the proper relationship to each other during assembly. One such system currently used today is known as the pin and lever positioning device or the "J-clip" system. This system, which will be described in further detail below with reference to some of the figures, includes a cable having one fixed end fitting attached to one end of the sheath and the other end of the sheath is positionable within a J-clip attached to a structure of the vehicle. Installation of this system requires that the control lever is held in a fixed position prior to and during installation as well as holding the mechanism which operates the door in a fixed position.
Problems occur with this system because the operator can inadvertently push or pull the cable conduit while attempting to press the sheath into the J-clip. This results in an incorrectly adjusted cable which prevents the temperature lever from traveling to both ends of its travel. It is also possible for the operator installing the system to fail to press the cable sheath fully into the J-clip and this results in the cable popping out of the J-clip and thus an inoperative lever or door.
With the J-clip system as well as other systems it is possible for the control lever positioning devices to become distorted and this can result in an improperly adjusted cable.
Another problem with the J-clip system is that the operator may fail to remove the mechanism which locks the door in its initial predetermined position. If this occurs, the control lever will not operate because it is locked in place by the door.
Another adjustable cable end fitting is disclosed in U.S. Pat. No. 4,805,479 (Brightwell) assigned to the assignee of the present invention. This adjustable cable end fitting has a first channel shaped member having resilient ribs and limbs on its inner surface and is connectable to the fixed structure of the vehicle. It also includes a second member in the form of a sleeve which fits over the outer sheath of the cable and has ribs on its outer surface. The sleeve is retained in the channel by the resilient limbs and also by an interlocking engagement with the ribs. This prevents relative longitudinal movement between the sleeve and the channel shaped member.
This device is intended to have the regulating valve or heater door held in a position corresponding to the indicated setting on the instrument panel. As in the J-clip device, it is possible for this initial positioning member to become distorted during handling or assembly operations resulting in a misadjusted cable after the positioning member is removed.
Further, since the limbs include a return portion or barb, the stated purpose of which is to inhibit removal of the sleeve from the channel after assembly, adjustment is extremely difficult after the sleeve is assembled in the channel shaped member.
This device also does not allow complete rotation over 360.degree. between the inner and outer member. Thus torsional forces on the sheath, which are induced by the twisted path that the cable and sheath must go through, cannot be readily relieved and this inhibits the assembly process.
Even though the intention of the Brightwell patent is to inhibit removal of the sleeve from the channel member, it has been found that the sleeve can be inadvertently pulled from the channel member during assembly.
Thus it is seen that many problems remain when installing cables with or without adjustment features in the end fittings.